Classification of disease: There are many types of ASDs. They are differentiated from each other by whether they involve other structures of the heart and how they are formed during the developmental process during early foetal development:

 The ostium secundum ASD is the most common type of ASD (6-10%) of all congenital heart diseases. OS-ASD = enlarged PFO, may also have a MVP

Definition: is characterized by a deficiency of the atrioventricular septum of the heart

Classification of disease: A variety of different classifications have been used, but the defects are usefully divided into “partial” and “complete” forms.

 Partial AVSD = defect in the primum or inferior part of the atrial septum but no direct intraventricular communication (ostium primum defect).

 Complete AVSD = there is a large ventricular component beneath either or both the superior or inferior bridging leaflets of the AV valve. The defect involves the whole area of the junction of the upper and lower chambers of the heart, i.e. where the atria join the ventricles

Epidemiology: this defect is associated to patients with Down’s syndrome (35-40% DS pts have an AVSD)

Pathophysiology: It is caused by an abnormal or inadequate fusion of the superior and inferior endocardial cushions with the mid portion of the atrial septum and the muscular portion of the ventricular septum.

Treatment: repair defects (open surgery / percutaneous endovascular methods). In neonate, if stable, hold off from doing repair until signs of resp distress or HF show, as this gives more time for the heart to grow and this increases efficacy of repair.

Can also use furosemide, ACEi and digoxin to ease symptoms prior to repair.

Prognosis: mortality of repair ~5-10%

Coarctation of the aorta

Definition: is a congenital condition whereby the aorta narrows in the area where the ductus arteriosus (ligamentum arteriosum after regression) inserts.

Classifications of disease: There are three types:

1. Preductal coarctation: The narrowing is proximal to the ductus arteriosus. This is the type seen in 5% of Turner Syndrome.

2. Ductal coarctation: The narrowing occurs at the insertion of the ductus arteriosus.

3. Postductal coarctation: The narrowing is distal to the insertion of the ductus arteriosus. Rib notching on CXR due to inc collateral supply

Pathophysiology: results in low pO2 of blood due to the mixing of oxygenated and deoxygenated blood in the left ventricle via the VSD and preferential flow of the mixed blood from both ventricles through the aorta because of the obstruction to flow through the pulmonary valve

Investigations: echo, CXR = ‘boot-shaped heart’.

Treatment: total surgical repair

Prognosis:

 Survival for untreated ToF: ~75% after the first year of life, 60% by four years, 30% by ten years, and 5% by forty years.

 Survival for treated patients: depends on pts heart and success of surgical repair, but much better

Transposition of great arteries (TGA)

with ‘egg on side’ sign on CXR

Definition: an abnormal spatial arrangement of the pulmonary artery and the aorta

Classification of disease: TGV is often accompanied by other heart defects, the most common type being ASDs (PFO), VSDs, PDAs. Stenosis, or other defects, of valves and/or vessels may also be present.

When no other heart defects are present = ‘simple’ TGV. Other defects are present = ‘complex’ TGV.

Epidemiology

 Transposition is the most common cyanotic congenital heart lesion presenting in the neonate.

 Annual incidence is 20-30 / 100,000 live births

 M>F (3:1)

 Transposition is rarely associated with syndromes or extracardiac malformations

Pathophysiology: PDA allows blood flow between the aorta and the pulmonary artery. PDA is common in neonates with persistent respiratory problems such as hypoxia. Has a high occurrence in premature children. In hypoxic newborns, too little oxygen reaches the lungs to produce sufficient levels of bradykinin and subsequent closing of the DA. Premature children are more likely to be hypoxic and thus have PDA because of their underdeveloped heart and lungs.

In TGA, a PDA may need to remain open. The PDA is the only way that oxygenated blood can mix with deoxygenated blood. In these cases, prostaglandins and low flow O2 are used to keep the PDA open until surgery can be performed to correct

Investigations: echo, ECG (tall R in V6), CXR (enlargement of the pulmonary arteries, veins, left atrium and left ventricle).